Weight Loss Injections in Australia: A GP's Guide

Loading... 202 view(s) 12 min read

(last updated May 2026)

Introduction

Weight loss injections have become a common topic in Australian weight management. Most people know someone who is taking them, have read about them online, or have wondered whether they may be worth trying themselves after struggling to lose weight.

They can be effective for many people, but they are prescription medicines, not retail products. Like any medication, they can cause side effects, and work best with medical assessment and follow-up.

Before starting treatment, it helps to understand a bit more these medicines, what a GP may be looking out for, what risks to discuss, and why ongoing review matters.

What Are Weight Loss Injections?

Weight loss injections are prescription medicines that may be used to support weight management when clinically appropriate. In everyday use, the phrase most often refers to injectable incretin-based medicines, including GLP-1 receptor agonists and dual GIP/GLP-1 receptor agonists.

These medicines affect biological pathways involved in hunger, fullness, digestion and blood glucose regulation. If you want a more detailed explanation of the science, you can read more here: [how incretin-based therapies work].

They are usually considered alongside nutrition, physical activity, sleep, alcohol intake, mental health, existing medical conditions and previous weight loss attempts. The injection sits within a treatment plan that also needs follow-up and longer-term support.

How do weight loss injections work?

Different injectable medicines work in slightly different ways. Many help people feel full sooner, reduce appetite or cravings, slow how quickly food leaves the stomach, and affect blood glucose regulation.

For some people, this makes it easier to reduce food intake and stay consistent with a treatment plan. The best results usually come when treatment is paired with regular meals, adequate nutrition, physical activity and sleep.

Response varies. Some people lose a meaningful amount of weight, some have a modest response, and others may end up stopping treatment because of side effects, cost, limited benefit, supply issues or personal preference.

Who are weight loss injections suitable for?

Injectable prescription medicines for weight management are generally considered for Australians with a BMI of 30 or above, or a BMI of 27 or above with at least one weight-related health issue. Examples include:

- high blood pressure

- insulin resistance or prediabetes

- fatty liver

- sleep apnoea

- osteoarthritis or weight-related joint pain

- abnormal cholesterol

- PCOS

As well as the eligibility criteria, the doctor and patient still need to consider whether the likely benefits, risks, side effects, cost and follow-up requirements make sense for the individual person.

What does a GP assess before prescribing weight loss injections?

A proper GP assessment is not simply a quick BMI check. Before recommending prescription weight loss treatment, a doctor may review important issues such as:

- your weight history and previous weight loss attempts

- your current body mass index and waist measurements.

- blood pressure, blood glucose, cholesterol and liver results

- current medicines, allergies and previous side effects

- pregnancy plans, pregnancy or breastfeeding

- eating patterns, appetite, alcohol intake and nutrition

- mental health, including eating disorder risk or significant mood symptoms

- past gallbladder, pancreatic, thyroid, kidney, liver or gastrointestinal problems

- whether follow-up appointments, blood tests or referrals are needed

- whether the treatment is affordable for the patient

What results can people expect?

If prescribed a weight loss injection, you’ll usually start with a low dose, gradually increasing to minimise side effects. Weight loss typically happens within 3-6 months, and lifestyle changes support lasting success.

Results vary. Clinical research (such as the STEP1 and SCALE trials) has shown that people using these medications can lose 5-15% body weight loss over 12-18 months. There are slight differences in results between the various available medications. It is important to note that some people do not respond as strongly to treatment, but even small reductions in weight can lead to improvements in blood pressure, blood glucose, fatty liver, sleep apnoea or joint pain.

And the long term results? These injections can maintain weight loss if continued, but data beyond 2-3 years is still emerging. Some studies (such as the STEP4 trial in 2021) have shown that patients regain a substantial amount of the lost weight after stopping (though lifestyle factors plays a significant part in this too).

Australian Prescriber summarises clinical trial averages ranging from about 8% to about 21% of starting body weight over 56 to 72 weeks, depending on the medicine and dose. Trial participants also received lifestyle advice, so the results may not reflect the injection alone.

Your own results will depend on several factors including the medicine prescribed, dose, side effects, health conditions, nutrition, physical activity, sleep, alcohol intake and follow-up care.

Side effects of weight loss injections

The most common side effects are usually gastrointestinal (affecting your stomach or gut). These may include:

- nausea

- vomiting

- reflux or indigestion

- constipation

- diarrhoea

- bloating or abdominal discomfort

- reduced appetite that feels too strong

- dehydration if vomiting or diarrhoea occur

Side effects are often more noticeable when treatment starts or when doses change. A doctor may reduce risk by starting carefully, increasing gradually where appropriate, and reviewing symptoms during follow-up.

Less common but more serious concerns can include pancreatitis, gallbladder disease, severe vomiting or dehydration, worsening reflux or stomach-emptying problems, and other medicine-specific risks. Seek urgent medical advice if you develop severe abdominal pain, persistent vomiting, jaundice, fainting, chest pain, severe allergic symptoms, or any symptom that is severe, worsening or concerning to you.

For a more detailed side-effect discussion, see our article on [GLP-1 side effects] .

Do weight loss injections cause muscle loss?

When people lose weight, some lean mass can be lost along with body fat. That is not unique to injections, but it matters because maintaining muscle supports strength, mobility, metabolic health and long-term function.

A medical weight management plan should consider more than the number on the scale. It may include:

- adequate protein intake

- resistance or strength-based exercise

- progressive physical activity

- dietitian support

- review if appetite becomes too low

- monitoring energy, strength and wellbeing over time

For more on this topic you can read our section on protein intake during medical weight loss.

How much exercise?

150 minutes of moderate exercise weekly is a good guideline to start with. It can be helpful to consult a personal trainer, exercise physiologist, physiotherapist to provide some proper structure for you.

How much protein is enough?

Daily dietary protein recommendations vary, but guidelines suggest 1.2-2.0 g/kg body weight daily. This can get a bit tricky to work out by yourself, so it is highly recommended to see a dietitian at least once, to figure out your individual requirements.

How much do weight loss injections cost in Australia?

Cost is a major consideration. Injectable prescription treatments used specifically for weight management are often paid for privately in Australia. The price increases in line with the dose, and pharmacy prices can vary slightly too.

Some medicines in this treatment group are PBS-listed for very specific indications such as type 2 diabetes, but that does not mean they are automatically subsidised for weight management.

The total cost may also include:

- the initial medical consultation

- the medicine, if prescribed

- follow-up reviews

- pathology or other investigations where needed

- dietitian, psychology or other allied-health support where helpful

Medicine prices and availability can change, so your doctor and pharmacist are the best people to help you understand likely costs at the time treatment is being considered. For a detailed breakdown, see [weight loss injection costs in Australia]

Who may need to avoid or delay treatment?

Weight loss injections are not appropriate for everyone.

Some people may need to avoid them, delay treatment, or get specialist advice first. This can include people who are pregnant or breastfeeding, planning pregnancy, have certain endocrine cancer histories, previous pancreatitis, significant gallbladder disease, severe gastrointestinal disease, complex diabetes-related issues, severe kidney or liver disease, active eating disorder concerns, or allergy to a relevant medicine.

Some medicines in this group can also slow stomach emptying. If you are having surgery, an endoscopy, dental sedation or another procedure involving anaesthesia or deep sedation, tell the treating team that you use one of these medicines so they can manage fasting and aspiration risk appropriately.

Even if none of these apply, your doctor may still need to check your medicines, blood results, eating patterns and follow-up needs before deciding whether treatment is appropriate.

eScripts, pharmacies and medication safety

If prescription treatment is appropriate, your doctor can send an eScript to your phone so you can fill it at a pharmacy of your choice.

Using a registered Australian pharmacy matters. The TGA has warned that compounded weight-loss products are not identical to TGA-approved medicines and have not been evaluated in the same way for safety, quality and efficacy. Since 1 October 2024, pharmacists can no longer compound GLP-1 receptor agonist products for supply.

Avoid overseas websites, social media sellers, unregistered imported products, compounded products promoted as equivalent to approved medicines, or services that make prescribing feel automatic. Prescription medicines should come through a proper clinical process and a legitimate Australian supply chain.

If you are unsure whether a medicine or pharmacy pathway is legitimate, ask your doctor or pharmacist before using it.

Is it common to regain weight if you stop?

Yes, many people regain weight after stopping injectable treatment, particularly if appetite returns and long-term behaviour supports are not in place.

Weight regain after stopping is common because appetite and weight-regulation signals can change when treatment stops. Long-term management often needs a plan beyond the first few months.

Before stopping, it is worth discussing the decision with your doctor. They can help review side effects, cost, goals, alternative options, and what support may help reduce regain.

In some cases, patients may choose to stay on a low maintenance dose.

Why ongoing GP review matters

Ongoing review is a key part of safe, effective treatment.

Follow-up appointments may be used to:

- review side effects

- check whether treatment is helping

- adjust dose or timing where appropriate

- review blood tests or other investigations

- discuss hydration, constipation, reflux or nausea

- monitor mental health and eating patterns

- plan nutrition, protein and physical activity support

- decide whether treatment should continue, pause or change

This is especially important if side effects are persistent, weight loss is faster or slower than expected, treatment becomes unaffordable, or you are thinking about stopping. If you need follow-up care, you can BOOK HERE.

The Bottom Line

Weight loss injections can be a helpful option for some people in Australia, but they are prescription medical treatments that need assessment, monitoring and a longer-term plan.

If you are considering treatment, speak with an Australian doctor who can assess your situation and help you understand your options.

You can book your initial consultation HERE

Frequently Asked Questions

Can injectable weight loss treatment be prescribed online in Australia?

Yes, if an Australian doctor assesses that it is clinically appropriate and safe for you. A telehealth consultation should include enough information about your health, medicines, risks and goals to support that decision.

Are weight loss injections safe?

They can be used safely for some people with proper medical assessment and follow-up, but they can cause side effects and they are not suitable for everyone. Your doctor should discuss the expected benefits, risks and review plan before treatment starts.

Do weight loss injections replace healthy eating and exercise?

No. They work best as part of a plan that may include nutrition support, physical activity, sleep, behaviour change and medical review.

How long do people stay on treatment?

There is no single timeframe. Some people stop because of side effects, cost, limited benefit or personal preference, while others continue for longer if treatment is helping and remains appropriate. Others may decide to stay on a long term low dose to prevent weight regain. Your doctor can help you review progress, plan follow-up and discuss what may happen if treatment is paused or stopped.

Can I use my own pharmacy?

Yes. With our service, Doctors for Weight Loss, if your doctor issues an eScript, you can take it to the pharmacy of your choice. Please note that pricing can vary between pharmacies.

Are compounded weight loss injections the same as approved medicines?

No. Compounded weight loss injections are not the same as TGA-approved medicines. The TGA says compounded products have not been evaluated for safety, quality and efficacy in the same way as registered medicines, and since 1 October 2024 pharmacists can no longer compound GLP-1 receptor agonist products for supply.

Patients should use medicines obtained through a registered Australian pharmacy after appropriate medical assessment.

What side effects should I seek urgent help for?

Seek urgent medical advice for severe abdominal pain, persistent vomiting, signs of dehydration, yellowing of the skin or eyes, fainting, chest pain, symptoms of a severe allergic reaction, or any symptom that is severe, worsening or concerning to you.